A data processing system having an analog-to-digital converter (ADC) and method for testing the ADC are provided. The data processing system also comprises a digital-to-analog converter (DAC) and test logic. The DAC has a first voltage range, an input for receiving a test code, and an output. The ADC has a second voltage range larger than the first voltage range, an input coupled to the output of the DAC, and an output for providing a series of output codes over the second voltage range. The test logic is coupled to the ADC and is for controlling testing of the ADC using the DAC. A plurality of series of test codes are provided to the DAC for testing portions of the second voltage range output from the ADC. A beginning series of test codes is for testing a beginning portion of the second voltage range and subsequent series of test codes are for testing subsequent portions of the second voltage range. Subsequent portions of the second voltage range are tested until a maximum voltage of the second voltage range of the ADC is reached.